The present invention relates to the creation of electrical energy storage modules and, more particularly, to electrical energy storage modules of high-energy storage capacity, comprising one or more capacitor-based electrical energy storage submodules. The individual modules may be of various size and storage capacity, and may be provided in various combinations and configurations for residential, commercial, industrial, telecommunications, utility and other uses. Each module may also be equipped with a variety of power conversion and control electronics. A number of modules may be connected to form an electrical energy storage module or system of larger capacity.
There are many situations wherein there is a need for a source of stored electrical energy. Such situations may include, for example, the need to provide electrical power to remotely located equipment that may not be supplied by power from a utility. Stored electrical energy may also be used to supply power to a residential, commercial or industrial customer during periods of utility power interruption, or to supplement power supplied thereto by a utility during periods of extreme demand. It is also desirable to store quantities of electrical energy sufficient to meet the demands of a residential, commercial or industrial customer for an extended period of time. In this manner, a customer may charge the storage device(s) during periods when the cost to purchase electrical energy is low, and discharge the device(s) to satisfy demand during periods when the cost to purchase electrical energy is higher. Consequently, such devices may be used in peak shaving or load-leveling systems to help electrical utilities meet peak demand.
The present invention provides such an electrical energy storage device. The present invention contemplates the use of capacitor-based electrical storage systems, comprised of one or more electrical energy storage modules of high-energy storage capacity. The capacitor-based electrical energy storage systems/modules of the present invention are preferably capable of operating at a nominal continuous rated power output for a period of several hours, and may also be able to operate at a reduced power output for significantly longer periods of time. The capacitor-based electrical energy storage systems/modules of the present invention are also preferably capable of a substantially higher power output of relatively short duration. Unlike many other electrical energy storage devices, the capacitor-based electrical energy storage modules of the present invention are also capable of performing load following, wherein the power output of a module(s) can automatically increase or decrease in response to changing demands thereon. Such systems/modules may be of stationary, fixed, or transportable design.
Each electrical energy storage module is comprised substantially of one or more capacitor-based electrical energy storage submodules located in a specialized enclosure or cabinet, and may also include a power conversion system (PCS) and control electronics. One or more cabinets, each having one or more submodules, may constitute a single module. The submodule contains the means for storing the electrical energy. Preferably, the submodule contains one or more capacitors designed to store electrical energy. Capacitors of various design and construction may be utilized in this regard, however, a capacitor of electrochemical type is preferred for its high energy density. Electrochemical capacitors are capable of having a high charge density, meaning that a considerable quantity of electrical energy may be stored in a relatively small volume. The submodule may also have other features, such as lifting means, a means of automatic electrical connection, and its own PCS and/or control electronics.
Each electrical energy storage submodule is preferably located and secured within a designated space of the enclosure or cabinet. The cabinet is preferably designed to have openings of predetermined size that are designed to act as both mechanical and electrical receptacles for receiving the submodules. The submodules and cabinet are typically adapted to allow a submodule to slide into each of the receptacles in the cabinet. Preferably, the cabinet is prewired so that when each submodule is inserted therein, a connecting means on that submodule will electrically connect it, via the cabinet wiring, to other submodules in the cabinet. The modules may be connected in series or parallel to produce a desired output. Wiring of the cabinet in this manner also allows each submodule to be charged from a single input location. Preferably, one or more receptacles are also provided in each cabinet to receive a PCS and/or control electronics.
One or more cabinets containing one or more submodules and/or power conversion and control electronics may be connected to produce a module of larger electrical energy storage and output capacity. The cabinets may be connected in series or parallel to obtain the desired storage capacity/power output. A transformer may be used in conjunction with a module to increase the module""s output voltage. A number of modules (e.g., three) with the appropriate power conversion electronics and/or transformer(s) may be combined to create a 3-phase power output (e.g., one module per phase) or, alternatively, a single module may produce a balanced 3-phase power output.
In alternate embodiments of the present invention, the cabinets for storing and connecting individual submodules may be open or may be enclosed. The cabinets may be designed to allow for insertion of the submodules, of which at least one side thereof will remain visible after installation. Such a cabinet may be used when the cabinet and submodules will not be exposed to inclement conditions. Such a cabinet also allows for easy access to each submodule, should a submodule need to be removed for repair or replacement. The cabinet may also be enclosed, such as by providing doors or other means for sealing off the cabinet after installation of the submodule(s). This type of cabinet may be used when it will be exposed to inclement conditions, such as may be encountered when the cabinet is located outdoors, or in a harsh indoor environment.
The design of the submodules, modules, and cabinets of the present invention allow for a high degree of flexibility in assembling a capacitor-based electrical energy storage system that can meet particular needs. Many of the systems are designed with the intent that the submodules may be installed/removed by hand; further adding to their flexibility. A multitude of configurations and capacities are possible, as can be seen by the reference to the following detailed description and related drawings.